Paschen-Back Effect of Hyperfine Structure and Polarization of Resonance Radiation. Cadmium (6P11−5S01)

Because of the Paschen-Back effect of the hyperfine structure of the odd isotopes, the polarization of cadmium $\lambda 2288\mathrm{A}$ resonance radiation excited by plane polarized incident light changes from 76.7 percent in zero field to 100 percent in a strong field parallel to the electric vector of the exciting light. The experimental results agree very closely with computations based on Goudsmit's modification of Darwin's theory of the Paschen-Back effect and give for the separation of the two levels into which the $6{}_{}{}^1{}_{}{}^{}P_1^{}{}_{}{}^{}$ level of Cd (odd-isotopes) is split a value of 12.6×${10}^{-3\mathrm{}}$ ${\mathrm{cm}}^{-1\mathrm{}}$. From this result and Schüler's measurements of the hyperfine separations of the triplet lines $6{}_{}{}^3{}_{}{}^{}P_{0,1,2}^{}{}_{}{}^{}-6\mathrm{}{}_{}{}^3{}_{}{}^{}S_1^{}{}_{}{}^{}$ the constants $a$ and $b$ giving the interactions of the $p$ and $s$ electrons, respectively, from Goudsmit's equation $A\left(J\right)=a(2-g)-a\frac{6\Gamma \mathrm{}(2-g)-2\mathrm{}(g-1\mathrm{})L(L+1\mathrm{})\mathrm{}}{\mathrm{}(2L-1)\mathrm{}(2L+3)\mathrm{}}+b(g-1\mathrm{})\mathrm{}$ are found to be $a=8.4\mathrm{}\times {10}^{-3\mathrm{}}$ and $b=225.7\mathrm{}\times {10}^{-3\mathrm{}}$.